A typical electrical wall outlet is one which has receptacles for the plugs for two separate electrical appliances. However, there are instances where the plugging in of a single appliance may block both of those receptacles. For instance, if the appliance has an overly large plug such as an adapter type plug, the plug itself will block both receptacles. In other instances, the plug may be mounted directly to the back of an appliance such as a wall mounted heater fan where the body of the fan blocks the other receptacle.
In the above example, it is possible to put a totally separate plug receptacle into the actual body of the first appliance plugged into the wall outlet. A second appliance can then be plugged into the first appliance whereby both appliances draw power from the same wall outlet.
One serious drawback resulting from the arrangement described immediately above, is that when both of the appliances are operating together they may draw more wattage than can be safely provided from the single outlet. Typically, an electrical wall outlet operates at a maximum of 1500 watts and if the two appliances together require more than 1500 watts, this results in an overloading of the circuit. For this reason, the inclusion of a separate plug has not been allowed to date, for an electrical heater fan having a maximum output at 1500 watts.